There is known an internal combustion engine including a port injection valve that injects fuel into an intake port, and a cylinder injection valve that directly injects fuel into a combustion chamber. The internal combustion engines are typically spark ignition type internal combustion engines, and include various modes of internal combustion engines that are equipped with a turbocharger, of a natural aspiration type, equipped with an EGR device and the like.
Japanese Patent Laid-Open No. 2010-053717 (hereinafter referred to as “Patent Literature 1”) discloses a control method of an internal combustion engine equipped with a turbocharger, which includes a port injection valve and a cylinder injection valve. According to the control method disclosed in Patent Literature 1, an operation by combustion by a theoretical air-fuel ratio (hereinafter, stoichiometric combustion) is performed in all operation ranges, by properly using an operation using only port injection by the port injection valve, an operation using only cylinder injection by the cylinder injection valve, and an operation using port injection and cylinder injection in combination, in accordance with an operation range which is determined by torque and a speed of the internal combustion engine. Performing an operation by stoichiometric combustion in the all operation ranges is one of the methods for enhancing emission performance.